Liquid crystal displays are commonly used as display devices for compact electronic apparatuses, because they are not only very thin but also provide good quality images with little power consumption.
A typical LCD device includes an LCD panel. The LCD panel includes two transparent substrates parallel to each other, and a liquid crystal layer disposed between the substrates. In order to enable the LCD device to display full-color images, a color filter is usually employed in the LCD device at one of the substrates. A typical color filter provides three primary colors: red, green, and blue (RGB). The color filter, the liquid crystal layer, and a switching element arranged on the substrate cooperate to provide the LCD device with full-color image display capability.
As shown in FIG. 3, a typical color filter 30 includes a substrate 300, a black matrix 310 disposed on the substrate 300, and a patterned photoresist layer 320 disposed in and around holes of the black matrix 310. A transparent overcoat layer 330 is arranged on and covers portions of the black matrix 310 and the photoresist layer 320. The substrate 300 functions as a carrier of the above-described elements. The photoresist layer 320 includes a multiplicity of pixel regions 321. Each pixel region 321 includes three sub-pixel regions: a red sub-pixel region 322, a green sub-pixel region 324, and a blue sub-pixel region 326, which are arranged in a predetermined pattern. The black matrix 310 is disposed in and around the sub-pixel regions 322, 324 and 326 of the pixel regions 321.
The photoresist layer 320 is generally made from organic components, such as a combination of polymer, surfactant, pigment, and monomer. However, the thermal resistance of the pigment is generally poor, which can result in poor color reproduction of the color filter 30.
To solve this problem, a plurality of nanoparticles can be doped into the photoresist material that is used for fabricating the photoresist layer 320. In general, there are two types of methods for manufacturing the nanoparticles: physical methods and chemical methods. Typical chemical methods include Chemical Vapor Deposition (CVD), precipitation, and the reverse micelle method. Diameters of the nanoparticles that are manufactured by conventional chemical methods are typically in the range from 5×10−8 meters to 2×10−7 meters. Light scattering often occurs when light beams pass through a color filter employing photoresist having these nanoparticles. This can result in reduced contrast and reduced light transmission of the color filter 30.
What is needed, therefore, is a method for manufacturing photoresist that can overcome the above-described deficiencies.